Ever increasing requirements for reducing the size of packaged semiconductor devices has led to the development of several different types of semiconductor packages. Generally speaking, reduced sizes of semiconductor devices use an inverted die that is directly attached to a substrate to thereby increase the density of external connections that are provided within the perimeter of the package.
One such package is known as a flip chip semiconductor package and sometimes comprises a flexible tape substrate with a pattern of runners with corresponding outer portions that are made available for interconnection to, for example, a printed circuit board. An inverted die is mounted to the substrate and the runners are soldered to pads on the die. With this package a relatively high density of runners can. be formed on the flexible substrate to provide a higher density of external connections. The flip chip semiconductor package with a flexible tape substrate is becoming a popular alternative to the conventional more rigid substrate packages. Currently, flip chip semiconductor packages are manufactured such that after the die is mounted to the flexible substrate to form an assembly. The assembly is preheated then an underfill material is dispensed onto the assembly in a heated dispensing zone. The underfill then starts to flow into a gap between the substrate and die. The assembly remains stationary in the dispensing zone to allow the underfill to be drawn into the gap by the effects of capillary action. The assembly is then conveyed to a cooling zone heat is removed from the assembly and the underfill material at least partially solidifies. The assembly is later reheated to cure the underfill and form the completed semiconductor package. However, in order to increase production rates, the assembly may be prematurely removed from the heated dispensing zone and the underfill may not have been completely drawn into the gap by the effects of capillary action. Alternatively, if the assembly is kept stationary in the heated dispensing zone until the underfill have been completely drawn into the gap, then this unnecessarily increases the time to manufacture underfilled semiconductor packages.